Study On The Water Quality Assessment Methods Of Water Function Zones Under Special Conditions

In order to solve the increasingly complex problem of the water environment andachieve highly efficient utilization of water resources and effective protection of thewater environment in our country, in2011, the Central Document No.1proposed toimplement The strictest management system of water resources and delimit “three redlines”, including one for total water supply control, the second one for waterutilization efficiency control and the third one for limiting pollutant capacity in waterfunction zones. In2012, The views of the State Council on implementing the moststringent management system of water resources ascertained that water qualificationrates would be taken as the assessment indicators for the determination of red line forlimiting pollutant capacity in water function zones and proposed that water qualitycompliance rates of water function zones should be raised to95%in2030. Therefore,the veracity and rationality of water function zones’ water quality assessment becomethe foundations of the implementation of the limiting pollutant capacity system.At present, Technical specifications of surface water quality assessment(SL395-2007) and Water quality assessment technical plan of the national importantrivers and lakes water function zones (2012) have regulated the water qualityassessment of the water function zone explicitly. However, restricted by factors suchas economic development, technology, natural geographical location and so on, thewater assessment practices have been facing difficulties: the exceeding of upstreamrunoff, the lacking of monitoring frequency, the substandard scenario analysis onwater quality in water function zones under the situation of the left and right banks’provincial boundary buffer, and the deficiency of water quality evaluation method ofwater function zones. These difficulties are considered to be a challenge for the waterquality compliance evaluation of water function zones and have become thebottleneck for implementing the most stringent management system of waterresources in China. This paper analyze problems of our country’s the current water pricing system inwater functional regions and the substandard circumstances, such as the exceeding ofupstream runoff, insufficient monitoring frequency, the left and right banks’ provincialboundary buffer and so on. This paper studied the evaluation methodologies for theexceeding of upstream runoff, the lacking of monitoring frequency and thedetermination of water quality standard of the left and right banks’ provincialboundary buffer, effectively fill up the blank of the technical specification of surfacewater quality assessment (SL395-2007) for water functional regions’ water qualityevaluation under special conditions, and provide technical support for theimplementation of the red-line of pollution limiting capacity system of water functionzones in China.Studies have shown that:(1) the water quality assessment results of downstreamwater function zones under a condition that water quality of upstream water isexceeding the standard are not justified. Whereas the assessment procedures of theexisting surface water resources quality do not incorporate specific disposal methodsto cope with the condition. According to relevant terms in Explanations of theassessment indicators for the implementation of water pollution preventionspecialized planning in key river basins, by deducting the exceeded flux from theactual measured pollutant flux of the objective fracture surface (??), this paperproposed two evaluation methods: establishing water quality simulation-fluxdeduction method and restricting total pollution emission-pollutant discharged in river.These two methods have been proved to be feasible in several examples.(2) Theinaccurate water quality assessment caused by the insufficient frequency due touncertaintiesand inadequate technology under insufficient monitoring scenario, asshown in this paper, can be evaluated through the identical water season dataalternative method, adjacent fracture surface derivation method, adjacent functionzones evaluating method and evaluation method of limiting total pollution emission-total pollutant discharged in river. The example verifications indicate that theevaluation results consistently match the practical situations, suggesting thesemethods are feasible.(3) The situation under which the water quality of the left and right provincial boundary buffering zones cannot be estimated because of the adjacentrelations of provinces could be accessed through provinces’ adjusting concentrationaccounting method, representative fracture surface judging method and evaluationmethod of limiting total pollution emission-total pollutant discharged in river toevaluate the reaching standard situation of water quality in water functional area. Theexample verification results display that these methods are practical.To summerize, the exceeding of upstream runoff, insufficient monitoringfrequency, the left and right banks’ provincial boundary buffer are the blind spots ofthe existing technical method. We should make the relevant evaluation methods andtechnical standards, so as to solve the difficulties of the exceeding of upstream runoff,insufficient monitoring frequency, the left and right banks’ provincial boundary buffer.